Marina Vildanova

New complex EAS installation of the Tien Shan mountain cosmic ray station

In this paper we present a description of the new complex installation for the study of extensive air showers which was created at the Tien Shan mountain cosmic ray station, as well as the results of the test measurements made there in 2014-2016. At present, the system for registration of electromagnetic shower component consists of ∼100 detector points built on the basis of plastic scintillator plates with the sensitive area of 0.25m2 and 1m2, spread equidistantly over ∼104 m2 space. The dynamic range of scintillation amplitude measurements is currently about (3 − 7) · 104, and there is a prospect of it being extended up to ∼106. The direction of shower arrival is defined by signal delays from a number of the scintillators placed cross-wise at the periphery of the detector system. For the investigation of nuclear active shower components there was created a multi-tier 55m2 ionization-neutron calorimeter with a sum absorber thickness of ∼1000g/cm2, typical spatial resolution of the order of 10cm, and dynamic range of ionization measurement channel about ∼105. Also, the use of saturation-free neutron detectors is anticipated for registration of the highand lowenergy hadron components in the region of shower core. A complex of underground detectors is designed for the study of muonic and penetrative nuclear-active components of the shower. The full stack of data acquisition, detector calibration, and shower parameters restoration procedures are now completed, and the newly obtained shower size spectrum and lateral distribution of shower particles occur in agreement with conventional data. Future studies in the field of 1014 − 1017eV cosmic ray physics to be held at the new shower installation are discussed.

Are there tachyons in extensive air showers

The results obtained by studying double-front extensive air showers in which more than 107 particles are contained and in which the fronts are separated by a time interval of Δt ∼ 100 ns are presented. Serious difficulties in explaining “delayed” showers are revealed. In this connection, a hypothesis that the “leading” showers are initiated by tachyons produced in the first interaction of primary particles is proposed.

Fast and simple glass-based charged particles detector with large linear detection range

In cosmic rays physics often a simple charged particle detector with fast response, best possible pulse time resolution and large linear range is required. For that purpose, we have developed a design that is based on the detection of Cherenkov radiation produced by charged particles in a thick optical glass used as a detection medium by a photomultiplier tube. In this work, the results of detector parameters simulation and experimental verification are presented.

Horizon-T experiment status

Horizon-T is an innovative detector system constructed to study Extensive Air Showers (EAS) in the energy range above 1016 eV coming from a wide range of zenith angles (0o–85o). The system is located at the Tien Shan High-altitude Science Station of the Lebedev Physical Institute of the Russian Academy of Sciences at ∼ 3340 meters above sea level. It consists of eight charged particle detection points separated by distances up to one kilometer as well as an optical detector subsystem to measure the Vavilov-Cherenkov light from the EAS. The time resolution of charged particles and Vavilov-Cherenkov light photons passage of the detector system is a few ns. This level of resolution allows conducting a research of the atmospheric development of individual EAS. This report focuses on a general description of the detector system and the individual sub-systems providing an overview of the operations and latest results.